Electric bending endoscope

ABSTRACT

An electric bending endoscope includes a temperature sensor that detects the temperature of a motor as a state value indicating the driving state of a bending drive unit. A bending control device comprises: a temperature detection unit that receives the data of the temperature detected by the temperature sensor; a record unit in which the limits of motor temperature inputted in advance are recorded; a comparison unit that compares the data of the temperature sent from the temperature detection unit with the limits of motor temperature recorded in the record unit; and a notification unit that notifies that the driving state of a motor is approaching the limit.

[0001] This application claims the benefit of Japanese Application No.2002-31429 filed in Japan on Feb. 7, 2002, the contents of which areincorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to an electric bending endoscopewhose bending section that adjoins a distal section of an insertion unitthereof is bent using a motor.

[0004] 2. Description of the Related Art

[0005] In the past, endoscopes have been widely utilized. The endoscopehas an elongated insertion unit thereof inserted into a body cavity,whereby an intracavitary organ or the like can be observed or, ifnecessary, various kinds of cures or treatments can be performed using atreatment instrument passed through a treatment instrument channel.Moreover, in the field of industries, the endoscope has the elongatedinsertion unit thereof inserted into a boiler, a turbine, an engine, achemical plant, or the like for the purpose of observing or inspectingthe internal flaws or corrosion.

[0006] The endoscope has a bending section, which can be bent freely,formed at the proximal side of a distal section of the elongatedinsertion unit. The endoscope has a bending operation input unit such asa bending operation lever or a joystick, or the like formed on anoperating unit thereof. The bending operation input unit is handled inorder to instruct or input a position to which the bending section isbent or a bending speed as a magnitude of bending. The endoscope hasbending operation wires thereof mechanically drawn or released accordingto the instructed or input magnitude of bending. Consequently, thebending section is bent.

OBJECTS AND SUMMARY OF THE INVENTION

[0007] Accordingly, an object of the present invention is to provide anelectric bending endoscope that enjoys excellent maneuverability and along service life while suppressing unnecessary bending operation of abending section.

[0008] Another object of the present invention is to provide an electricendoscope that notifies an operator that the service life will soonterminate and that offers excellent safety.

[0009] An electric bending endoscope in accordance with the presentinvention comprises: an elongated insertion unit; a bending section thatadjoins a distal section of the insertion unit; a bending drive unitthat drives the bending section to bend; a bending operation input unitfor use in instructing bending of the bending section; a state detectionunit that detects the driving state of the bending drive unit; a recordunit in which the limits of abilities of the bending drive unit arerecorded; a comparison unit that compares the driving state detected bythe state detection unit with the limits recorded in the record unit;and a control unit that when the results of comparison sent from thecomparison unit demonstrate that the driving state of the bending driveunit has reached a limit, notifies a user of the driving state of thebending drive unit.

[0010] Moreover, an electric bending endoscope in accordance with thepresent invention comprises: an elongated insertion unit; a bendingsection adjoining a distal section of the insertion unit; a bendingdrive unit that drives the bending section to bend; a bending operationinput unit for use in instructing bending of the bending section; astate detection unit that detects the driving state of the bending driveunit; a record unit in which the limits of abilities of the bendingdrive unit are recorded; a comparison unit that compares the drivingstate detected by the state detection unit with the limits recorded inthe record unit; and a control unit that when the results of comparisonsent from the comparison unit demonstrate that the driving state of thebending drive unit has reached the limit, stops supply of energy to thebending drive unit.

[0011] Moreover, an electric bending endoscope in accordance with thepresent invention comprises: an elongated insertion unit; a bending unitadjoining a distal section of the insertion unit; a bending drive unitthat drives the bending section to bend; a bending operation input unitfor use in instructing bending of the bending section; a state detectionunit that detects the driving state of the bending drive unit; a recordunit in which the limits of abilities of the bending drive unit arerecorded; a comparison unit that compares the drive state detected bythe state detection unit with the limits recorded in the record unit;and a control unit that when the results of comparison sent from thecomparison unit demonstrate that the driving state of the bending driveunit has reached the limit, disconnects transmission of power exerted bythe bending drive unit.

[0012] Other features of the present invention and the advantagesthereof will be apparent from the description made below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 shows the overall configuration of an electric bendingendoscope system including a first embodiment of the present invention;

[0014]FIG. 2 shows the outline configuration of the electric bendingendoscope system shown in FIG. 1;

[0015]FIG. 3 is a flowchart describing bending control performed in theendoscope system shown in FIG. 2;

[0016]FIG. 4 is a graph indicating a joystick tilting speed calculatedbased on the (handling) time during which a joystick is handled and aninclination;

[0017]FIG. 5 is a flowchart describing bending control based on thecalculation whose results are graphically shown in FIG. 4;

[0018]FIG. 6 shows the outline configuration of an electric bendingendoscope system including a second embodiment of the present invention;

[0019]FIG. 7 is a flowchart describing bending control performed in theelectric bending endoscope system shown in FIG. 6;

[0020]FIG. 8 shows the outline configuration of an electric bendingendoscope system including a third embodiment of the present invention;

[0021]FIG. 9 is a flowchart describing bending control performed in theelectric bending endoscope system shown in FIG. 8;

[0022]FIG. 10 shows the outline configuration of a variant of theelectric bending endoscope system shown in FIG. 8;

[0023]FIG. 11 is a flowchart describing bending control performed in theelectric bending endoscope system shown in FIG. 10;

[0024]FIG. 12 is a graph indicating the bending speed of a bendingsection in relation to a motor driving signal that is sent from a motoramplifier under the control of a control unit;

[0025]FIG. 13 is a graph indicating a handling speed signal sent from ajoystick in relation to a handling speed at which the joystick ishandled under the control of the control unit;

[0026]FIG. 14 shows the outline configuration of a variant of anelectric bending endoscope system which extends control according to thegraph of FIG. 13;

[0027]FIG. 15 shows the outline configuration of an electric bendingendoscope system including a fourth embodiment of the present invention;

[0028]FIG. 16 is a longitudinal sectional view showing the joint of abending section and a flexible tube, which are included in the electricbending endoscope system shown in FIG. 15, and its surroundings;

[0029]FIG. 17 is a flowchart describing bending control performed in theelectric bending endoscope system shown in FIG. 15;

[0030]FIG. 18 shows the outline configuration of an electric bendingendoscope system including a fifth embodiment of the present invention;

[0031]FIG. 19A is a partly sectional view showing an endoscope insertionunit;

[0032]FIG. 19B is a schematic sectional view showing a tension sensorincluded in the insertion unit shown in FIG. 19A;

[0033]FIG. 20 is a flowchart describing bending control to be performedin the electric bending endoscope system shown in FIG. 18;

[0034]FIG. 21A is a sectional view schematically showing a tensionsensor of a first variant;

[0035]FIG. 21B is a sectional view schematically showing a tensionsensor of a second variant;

[0036]FIG. 22A is a partly sectional view showing an endoscope insertionunit that is a variant of the endoscope insertion unit shown in FIG.19A;

[0037]FIG. 22B is a sectional view schematically showing a tensionsensor shown in FIG. 22A;

[0038]FIG. 23A is a partly sectional view showing an endoscope insertionunit that is another variant of the endoscope insertion unit shown inFIG. 19A.

[0039]FIG. 23B is a sectional view schematically showing the tensionsensor shown in FIG. 23A;

[0040]FIG. 24 schematically shows the configuration of an electricbending endoscope system including a sixth embodiment of the presentinvention; and

[0041]FIG. 25 is a flowchart describing bending control to be performedin the electric bending endoscope system shown in FIG. 24.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] Referring to the drawings, embodiments of the present inventionwill be described below.

[0043] First Embodiment

[0044]FIG. 1 to FIG. 7 are explanatory diagrams concerning an electricbending endoscope in accordance with a first embodiment of the presentinvention.

[0045] First Embodiment FIG. 1 to FIG. 5 are concerned with a firstembodiment of the present invention.

[0046] As shown in FIG. 1, an electric bending endoscope system 1including the first embodiment of the present invention comprises: anelectric bending endoscope 2 that has a bending drive unit (see FIG. 2)which electrically bends a bending section that will be described laterand that adjoins a distal section of an insertion unit; a light sourcedevice 3 that supplies illumination light to the electric bendingendoscope 2; a video processor 4 that processes a signal produced by animaging unit that will be described later and that is incorporated inthe electric bending endoscope 2; and a bending control device 5 thatdrives and controls the bending drive unit included in the electricbending endoscope 2. The video processor 4 is connected to a monitorthat is not shown, and transmits a video signal to the monitor so thatan endoscopic image will be displayed.

[0047] The electric bending endoscope 2 has an operating unit 7 that isformed at the proximal end of an insertion unit 6 and that serves as agrip 7 a. The electric bending endoscope 2 has a soft universal cord 8extended from the lateral side of the operating unit 7. A light guideand signal cable which are not shown lie through the universal cord 8. Aconnector unit 9 is fixed to an end of the universal cord 8. Theconnector unit 9 includes: a light guide connector (hereinafter, LGconnector) 9 a that is coupled to the light source device 3 so that itcan be freely decoupled; a video connector 9 b which is located at theside of the LG connector 9 a and into which a connection cable 4 aextending from the video processor 4 is plugged so that it can beunplugged freely; and an angle connector 9 c into which a connectioncable 5 a extending from the bending control device 5 is plugged so thatit can be unplugged freely.

[0048] The endoscope insertion unit 6 (that is, the insertion unit 6 ofthe electric bending endoscope 2) has a hard distal section 11 that isprovided at a distal part of the insertion unit, a bending section 12that is located at the proximal end of the distal section 11 and can bebent freely, and a flexible tube 13, which is located at the proximalend of the bending section 12 and which is elongated and flexible,concatenated in that order.

[0049] The endoscope operating unit 7 (that is, the operating unit 7 ofthe electric bending endoscope 2) has the grip 7 a, which is a regionheld by a user, as a proximal part thereof. The endoscope operating unit7 has a plurality of video switches 14 a, which is used to remotelycontrol the video processor 4, arranged on the top of the grip 7 a.Moreover, the endoscope operating unit 7 has an air/water button 15 thatis used to supply air or water, and a suction button 16, which is usedto perform suction, arranged on the lateral side thereof.

[0050] Furthermore, the endoscope operating unit 7 has a treatmentinstrument insertion port 17, through which a treatment instrument suchas biopsy forceps are inserted, formed near the front end of the grip 7a. The treatment instrument insertion port 17 internally communicateswith a treatment instrument passage channel that is not shown. Atreatment instrument such as forceps that is not shown is insertedthrough the treatment instrument insertion port 17, and the tip of thetreatment instrument passed through an internal treatment instrumentpassage channel is jutted out of a channel opening that is formed in thedistal section 11 and a biopsy or the like can be performed.

[0051] Moreover, the endoscope operating unit 7 has a bending operationinput unit 20 that is used to instruct bending of the bending section12, such as, a joystick or a trackball.

[0052] As shown in FIG. 2, the electric bending endoscope 2 has a lightguide 21, over which illumination light is propagated, passed throughthe insertion unit 6. The proximal end of the light guide 21 isterminated at the connector unit 9 of the universal cord 8 by way of theoperating unit 7. Thus, illumination light emanating from a light sourcelamp, which is not shown and incorporated in the light source device 3,falls on the proximal end of the light guide 21. The illumination lightpropagated over the light guide 21 illuminates an object such as alesion through a distal surface of an illumination window that is notshown and that is locked in the distal insertion unit section 11 via anillumination optical system 22.

[0053] The illuminated object has its object image captured through anobservation window that is not shown and that adjoins the illuminationwindow. The captured object image is picked up and photoelectricallyconverted by an imaging unit 24, which includes a charge-coupled device(CCD) or the like, via an objective optical system 23. Thus, the objectimage is converted into an image signal. The image signal is transmittedover a signal cable 24 a extending from the imaging unit 24, and appliedto the video connector 9 b of the universal cord 8 via the operatingunit 7. Thus, the image signal is transmitted to the video processor 4over the connection cable 4 a.

[0054] The video processor 4 processes the image signal sent from theimaging unit 24 incorporated in the electric bending endoscope 2, andproduces a standard video signal so that an endoscopic image will bedisplayed on the monitor.

[0055] The distal insertion unit section 11 of the electric bendingendoscope 2 has the leading bending piece 25 a out of a plurality ofbending pieces 25, which constitutes the bending section 12 and isconcatenated so that the plurality of bending pieces can revolve freely,coupled to the proximal end thereof. On the other hand, the trailingbending piece 25 b out of the bending pieces 25 is coupled to the distalend of the flexible tube 13.

[0056] The insertion unit 2 has bending operation wires 26, which areused to bend the bending section 12 in upward, downward, rightward, andleftward directions of a field of view for observation, passed throughit. The tips of the bending operation wires 26 are respectively fixed tothe leading bending piece 25 a by brazing, or the like at positions ofthe bending section 12 associated with the upward, downward, rightward,and leftward directions. Consequently, by drawing or releasing thebending operation wires 26 associated with the directions, the bendingsection 12 is bent in a desired direction and the distal section 11 isangled in the desired direction.

[0057] The bending operation wires 26 are drawn or released by thebending drive unit 30, whereby the bending section 12 is electricallybent. Incidentally, FIG. 2 shows two of the bending operation wires 26associated with the upward and downward directions or rightward andleftward directions.

[0058] The bending drive unit 30 includes a sprocket 31 that holds theproximal parts of the bending operation wires 26 while having theproximal parts wound thereabout and that draws or releases the bendingoperation wires 26, and a motor 32 that rotates the sprocket 31.

[0059] The bending drive unit 30 has a clutch 33, which disconnectstransmission of driving force exerted by the motor 32, interposedbetween the sprocket 31 and motor 32. Consequently, the bending driveunit 30 can disconnect transmission of the driving force exerted by themotor 32 using the clutch 33, and establish a bending operationwires-freed state. The clutch 33 is operated under the control of acontrol unit that will be described later and incorporated in thebending control device 5. The clutch 33 may be designed to be operatedmanually.

[0060] A signal line 32 a extending from the motor 32 is led to theangling connector 9 c of the universal cord 8. A motor driving signal istransmitted from a motor amplifier 34 included in the bending controldevice 5 to the motor 32 over the connection cable 5 a. The motoramplifier 34 is connected to a control unit 35 and controlled and drivenby the control unit 35.

[0061] The motor 32 includes an encoder 36 that serves as a member of arotational position detection unit so as to help detect a rotationalposition. A signal line 36 a extending from the encoder 36 is led to theangling connector 9 c of the universal cord 8. A rotational positionsignal indicating the detected rotational position of the motor 32 istransmitted to the control unit 35 over the signal line 36 a.

[0062] The sprocket 31 converts the rotational motion of the motor 32into the advancing or withdrawing motions of the bending operation wires26. A potentiometer 37 that serves as a member of the rotationalposition detection unit so as to help detect the rotational position isconnected to the sprocket 31. A signal line 37 a extending from thepotentiometer 37 is led to the angling connector 9 c of the universalcord 8. A rotational position signal indicating the rotational positionof the sprocket 31 is transmitted to the control unit 35 over the signalline 37 a.

[0063] Reference numeral 38 denotes a clutch operation detecting switch38 that detects whether the clutch 33 is activated or inactivated. Asignal line 38 a extending from the clutch action detecting switch 38 isled to the angling connector 9 c of the universal cord 8. A clutchaction signal indicating the detected action of the clutch 33 istransmitted to the control unit 35 over the signal line 38 a.

[0064] Moreover, as mentioned above, the electric bending endoscope 2has the bending operation input unit 20 such as a joystick or atrackball formed on the grip 7 a of the operating unit 7. A signal line20 a extending from the bending operation input unit 20 is led to theangling connector 9 c of the universal cord 8. A bending operationsignal indicating an instructed bending operation is transmitted to thecontrol unit 35 over the signal line 20 a.

[0065] In response to the bending operation signal sent from the bendingoperation input unit 20, the control unit 35 controls the motoramplifier 34 so as to drive the motor 32 according to the signals sentfrom the encoder 36 and potentiometer 37 which constitute the rotationalposition detection unit. Thus, the control unit 35 causes the bendingsection 12 to bend.

[0066] Herein, when the bending section 12 of a conventional electricbending endoscope is bent over a prolonged period of time, thetemperature of the motor 32 rises and the bending section 12 is drivenunstably. Consequently, the bending section 12 is bent withoutoperator's intention.

[0067] According to the present embodiment, the electric bendingendoscope 2 has the driving state of the motor 32 thereof detected. Thedetected driving state is compared with the limits of the driving staterecorded in advance. When the results of the comparison demonstrate thatthe driving state of the motor 32 has reached a limit, the driving stateof the motor 32 is notified. Furthermore, in the present embodiment,when the results of the comparison demonstrate that the driving state ofthe motor 32 has reached the limit, supply of energy to the motor 32incorporated in the electric bending endoscope 2 is stopped ortransmission of power exerted by the motor 32 is disconnected.

[0068] Specifically, according to the present embodiment, the electricbending endoscope 2 includes a temperature sensor 40 that detects thetemperature of the motor 32 as a state value indicating the drivingstate of the bending drive unit 30, such as, a thermistor or athermocouple or the like. The bending control device 5 includes: atemperature detection unit 41 that receives temperature data produced bythe temperature sensor 40; a record unit 42 in which the limits of motortemperature inputted in advance are recorded; a comparison unit 43 thatcompares the temperature data sent from the temperature detection unit41 with the limits of motor temperature recorded in the record unit 42;and a notification unit 44 that notifies that the driving state of themotor 32 is approaching the limit.

[0069] The temperature sensor 40 is realized with a thermistor or athermocouple. A signal line 40 a extending from the temperature sensor40 is led to the angling connector 9 c of the universal cord 8.Temperature data is transmitted to the temperature detection unit 41included in the bending control device 5 over the connection cable 5 a.

[0070] The notification unit 44 is a warning lamp realized with an LEDor the like in the present embodiment. The notification unit 44 may be abuzzer or a sound generation unit that generates an electronic sound orany other sound instead of the warning lamp. The notification unit 44may be designed so that a message will be displayed on a monitor that isnot shown.

[0071] The temperature detection unit 41 receives the data oftemperature, which is detected by the temperature sensor 40, as a motortemperature t, and transmits the motor temperature t to the comparisonunit 43.

[0072] In the record unit 42, a sublimit t1 immediately preceding alimit and the limit t2 that are inputted in advance are recorded as thelimits of motor temperature. The recorded limits are transmitted to thecomparison unit 43.

[0073] The comparison unit 43 compares the motor temperature t sent fromthe temperature detection unit 41 with the sublimit t1 and limit t2 readfrom the record unit 42, and transmits the results of comparison to thecontrol unit 35.

[0074] The temperature detection unit 41, record unit 42, and comparisonunit 43 are connected to the control unit 35, though the connections arenot shown. The temperature detection unit 41, record unit 42, andcomparison unit 43 are controlled based on control signals sent from thecontrol unit 35. The temperature detection unit 41, record unit 42, andcomparison unit 43 may be realized with software and installed in thecontrol unit 35.

[0075] The control unit 35 controls, as described in the flowchart ofFIG. 3 that will be referred to later, the notification unit 44according to the results of comparison sent from the comparison unit 43.When the driving state of the motor 32 reaches the limit, the motor 32is stopped or the bending section 12 is brought to the bending operationwires-freed state.

[0076] The electric bending endoscope 2 having the foregoing componentsis, as described in conjunction with FIG. 1, connected to the lightsource device 3, video processor 4, and bending control device 5, andused for endoscopic examination or the like.

[0077] An operator holds the grip 7 a of the electric bending endoscope2 so as to perform endoscopic examination. During the endoscopicexamination, the operator handles the bending operation input unit 20such as a joystick, or the like so as to bend the bending section 12.

[0078] The control unit 35 activates the motor amplifier 34 and reads acommand (bending operation signal) inputted at the bending operationinput unit 20. The control unit 35 calculates an angle of rotation ofthe motor from the read command (bending operation signal) sent frombending operation input unit 20. The calculated value is transmitted tothe motor amplifier 34, whereby the motor amplifier 34 is informed ofthe angle of rotation of the motor. The motor amplifier 34 in turndrives the motor 32 so that the motor will rotate by the informed angleof rotation of the motor.

[0079] Driving force exerted by the motor 32 is conveyed to the sprocket31 via the clutch 33, whereby the sprocket 31 rotates. The bendingoperation wires 26 fixed to the sprocket 31 are drawn or released. Thiscauses the bending section 12 to bend in a predetermined manner.

[0080] Herein, when the bending section 12 of the electric bendingendoscope 2 is bent over a prolonged period of time, the temperature ofthe motor 32 rises. At this time, the electric bending endoscope 2 hasthe bending of the bending section 12 thereof controlled as described inthe flowchart of FIG. 3.

[0081] As described in FIG. 3, first, the temperature sensor 40 measuresor detects the temperature of the motor 32 (step S1), and transmits thedata of the detected temperature of the motor 32 to the temperaturedetection unit 41 included in the bending control device 5. Thetemperature detection unit 41 in turn receives the temperature data sentfrom the temperature sensor 40 as a motor temperature t, and transmitsthe motor temperature t to the comparison unit 43 in response to anoutput signal of the control unit 35.

[0082] On the other hand, the record unit 42 transmits the sublimit t1and the limit t2 of motor temperature, which are recorded, to thecomparison unit 43 in response to the output signal of the control unit35. The comparison unit 43 compares the motor temperature t sent fromthe temperature detection unit 41 with the sublimit t1 and limit t2 readfrom the record unit 42, and transmits the results of comparison to thecontrol unit 35.

[0083] Based on the results of comparison sent from the comparison unit43, the control unit 35 determines whether the motor temperature t hasreached the sublimit t1 (step S2). When the control unit 35 determinesthat the motor temperature t has reached the sublimit t1, the controlunit 35 transmits a lighting signal so as to light the warning lamp(step S3). Consequently, the control unit 35 notifies that the drivingstate of the motor 32 is approaching the limit.

[0084] Furthermore, the control unit 35 determines whether the motortemperature t has reached the limit t2 (step S4). When the control unit35 determines that the motor temperature t has reached the limit t2, thecontrol unit 35 transmits a motor stop signal to the motor amplifier 34so as to stop the motor 32. Otherwise, the control unit 35 transmits aclutch off signal so as to inactivate the clutch, and brings the bendingsection 12 to the bending operation wires-freed state (step S5).Consequently, when the driving state of the motor 32 reaches the limit,the control unit 35 does not permit transmission of driving forceexerted by the motor 32 to the sprocket 31. Therefore, the bendingsection 12 will not be bent without operator's intention.

[0085] On the other hand, when the results of comparison sent from thecomparison unit 43 demonstrate that the motor temperature t is equal toor smaller than the sublimit ti or ranges from the sublimit t1 to thelimit t2, the control unit 35 extends control so that the bendingsection 12 will be bent normally (step S6).

[0086] Consequently, the temperature of the motor 32 included in theelectric bending endoscope 2 of the present embodiment is detected andcompared with the limits recorded in advance. When the motor temperaturereaches the sublimit, the fact is notified. Moreover, when the motortemperature reaches the limit, supply of energy to the motor 32 isstopped or transmission of power exerted by the motor 32 isdisconnected.

[0087] Consequently, the unnecessary bending of the bending section 12of the electric bending endoscope 2 of the present embodiment can besuppressed. The maneuverability of the bending section 12 can beimproved and the service life thereof can be extended.

[0088] When the bending operation input unit 20 is realized with ajoystick, the control unit 35 included in the bending control device 5can calculate, as seen from the graph of FIG. 4, a joystick tiltingspeed from the inclination angle of the joystick and the (handling) timethereof.

[0089] Control may be extended as described in the flowchart of FIG. 5.

[0090] As described in FIG. 5, the control unit 35 included in thebending control device calculates the joystick tilting speed from theinclination of the joystick and the time (step S1′).

[0091] Thereafter, the control unit 35 determines based on the result ofcalculation whether a change in the joystick tilting speed is made in anabrupt manner (step S2′). When the calculated value is equal to orlarger than a pre-set predetermined value, the control unit 35determines whether a change in the joystick tilting speed is made in anabrupt manner.

[0092] When the control unit 35 determines that a change in the joysticktilting speed is not made in an abrupt manner, the control unit 35determines based on a detection signal sent from an intention sensor 39whether a bending operation action instructed by handling the joystickis validated (step S3′).

[0093] When a bending operation action instructed by handling thejoystick is validated, the control unit 35 extends control so that thebending section 12 will be bent normally (step S4′).

[0094] On the other hand, when the control unit 35 determines that abending operation action instructed by handling the joystick isinvalidated or that a change in the joystick tilting speed is made in anabrupt manner, the control unit 35 generates a warning sound. Moreover,the control unit 35 inactivates the motor amplifier 34 so as to stop themotor 32 (step S5′).

[0095] The bending section 12 of the electric bending endoscope 2 can bebent as mentioned above.

[0096] Consequently, bending the bending section 12 of the electricbending endoscope 2 of this variant without operator's intention can beprevented.

[0097] The electric bending endoscope 2 of the present embodiment hasthe present invention adapted to an electronic endoscope having theimaging device 24, which picks up a received object image, incorporatedin the distal insertion unit section 11. The present invention is notlimited to the electronic endoscope. Needless to say, the presentinvention may be adapted to an optical endoscope that includes an imagetransmission unit which conveys a received object image. Herein, theobject image conveyed by the image transmission unit can be viewedthrough an eyepiece unit located at the rear end of an operating unit.

[0098] Moreover, the electric bending endoscope 2 of the presentembodiment is detachably connected to the bending control device 5. Thebending control device 5 drives or controls the bending drive unit 30.The present invention is not limited to this mode. Alternatively, thebending control device 5 may be incorporated in the electric bendingendoscope 2.

[0099] Second Embodiment

[0100]FIG. 6 and FIG. 7 are concerned with a second embodiment of thepresent invention.

[0101] According to the first embodiment, the temperature of the motor32 is detected as a state value indicating the driving state of thebending drive unit 30, and compared with recorded limits. According tothe second embodiment, a current and a voltage serving as a motordriving signal are detected as state values indicating the driving stateof the bending drive unit 30, and compared with the recorded limits. Theother constituent features are identical to those of the firstembodiment. The description of the constituent features will be omitted.Moreover, components identical to those of the first embodiment will bedescribed with the same reference numerals assigned thereto.

[0102] As shown in FIG. 6, an electric bending endoscope system 50including the second embodiment of the present invention is configuredso that a current and a voltage serving as a motor driving signal willbe detected as state values indicating the driving state of the bendingdrive unit 30, and compared with recorded limits.

[0103] To be more specific, a bending control device 5B includes: acurrent detection unit 51 that detects a current serving as a motordriving signal, which is transmitted from the motor amplifier 34, as astate value indicating the driving state of the bending drive unit 30included in the electric bending endoscope 2; a voltage detection unit52 that detects a voltage serving as the motor driving signal; a recordunit 42 b in which the limits of the current and voltage serving as themotor driving signal which are inputted in advance are recorded; acomparison unit 43 b that compares the data items of the current andvoltage, which are detected by the current detection unit 51 and voltagedetection unit 52 respectively, with the limits of the current andvoltage recorded in the record unit 42 b.

[0104] The current detection unit 51 receives the current data detectedover the signal line 32 a as a motor driving current I, and transmitsthe motor driving current I to the comparison unit 43 b. Noted is thatthe motor driving current I is a state value proportional to the torqueexerted by the motor. The voltage detection unit 52 receives the voltagedata, which is detected over the signal line 32 a, as a motor drivingvoltage V, and transmits the motor driving voltage V to the comparisonunit 43 b. Noted is that the motor driving voltage V is a state valueproportional to the rotating speed of the motor.

[0105] In the record unit 42 b, a sublimit I1 immediately preceding alimit and the limit I2 which are inputted in advance are recorded as thelimits of the motor driving current, and a sublimit V1 immediatelypreceding a limit and the limit V2 which are inputted in advance arerecorded as the limits of the motor driving voltage. The recorded limitsare transmitted to the comparison unit 43 b.

[0106] The comparison unit 43 b compares the motor driving voltage Vsent from the current detection unit 51 with the sublimit I1 and limitI2 read from the record unit 42 b, and then transmits the results of thecomparison to the control unit 35. The comparison unit 43 b thencompares the motor driving voltage V sent from the voltage detectionunit 52 with the sublimit V1 and limit V2 read from the record unit 42b, and then transmits the results of the comparison to the control unit35.

[0107] The current detection unit 51, voltage detection unit 52, recordunit 42 b, and comparison unit 43 b are connected to the control unit35, though the connections are not shown. The current detection unit 51,voltage detection unit 52, record unit 42 b, and comparison unit 43 bare controlled with control signals sent from the control unit 35.Incidentally, the current detection unit 51, voltage detection unit 52,record unit 42 b, and comparison unit 43 b may be realized with softwareand installed in the control unit 35.

[0108] The control unit 35 controls, as described in the flowchart ofFIG. 7, the notification unit 44 according to the results of thecomparisons sent from the comparison unit 43 b. When the driving stateof the motor 32 reaches the limit, the control unit 35 stops the motor32 or brings the bending section 12 to the bending operation wires-freedstate.

[0109] The electric bending endoscope 2 thus configured is, similarly tothe one described in relation to the first embodiment, connected to thelight source device 3, video processor 4, and bending control device 5B,and used for endoscopic examination or the like.

[0110] An operator holds the grip 7 a of the electric bending endoscope2 so as to perform endoscopic examination. During the endoscopicexamination, the operator handles the bending operation input unit 20such as a joystick, or the like so as to bend the bending section 12.

[0111] When the bending section 12 of the electric bending endoscope 2is bent over a prolonged period of time, the motor driving signal sentfrom the motor amplifier 34 to the motor 32 rises. At this time, theelectric bending endoscope 2 has the bending of the bending section 12thereof controlled as described in the flowchart of FIG. 7.

[0112] As shown in FIG. 7, first, the current detection unit 51 measuresor detects the motor driving current I (step S1). In response to anoutput signal of the control unit 35, the current detection unit 51transmits the detected motor driving current I to the comparison unit43. At the same time, the voltage detection unit 52 measures or detectsthe motor driving voltage V (step S12), and transmits the detected motordriving voltage V to the comparison unit 43 in response to the outputsignal of the control unit 35.

[0113] On the other hand, from the record unit 42 b, the sublimit I1immediately preceding the limit of the motor driving current and thelimit I2, which are recorded in the record unit 42 b, are transmitted inresponse to an output signal of the control unit 35. Moreover, thesublimit V1 immediately preceding the limit of the motor driving voltageand the limit V2 are transmitted to the comparison unit 43 b.

[0114] The comparison unit 43 b compares the motor driving current Isent from the current detection unit 51 with the sublimit I1 and limitI2 read from the record unit 42, and transmits the results of thecomparison to the control unit 35. Moreover, the comparison unit 43 bcompares the motor driving voltage V sent from the voltage detectionunit 52 with the sublimit V1 and limit V2 read from the record unit 42b, and transmits the results of the comparison to the control unit 35.

[0115] The control unit 35 determines based on the results of comparisonsent from the comparison unit 43 b whether the motor driving current Ihas reached the sublimit I1 (step S13). When the control unit 35determines that the motor driving current I has reached the sublimit I1,the control unit 35 transmits a lighting signal so as to light thewarning lamp (step S14). Thus, the control unit 35 notifies that thedriving state of the motor 32 is approaching a state in which the motor32 exerts an excessive torque.

[0116] Furthermore, the control unit 35 determines whether the motordriving current I has reached the limit I2 (step S15). When the controlunit 35 determines that the motor driving current I has reached thelimit I2, the control unit 35 stops the motor 32 or inactivates theclutch so as to bring the bending section 12 to the bending operationwires-freed state (step S16) in the same manner as the one described inrelation to the first embodiment. Consequently, when the driving stateof the motor 32 reaches the state in which the motor 32 exerts anexcessive torque, the control unit 35 does not permit transmission ofdriving force exerted by the motor 32 to the sprocket 31.

[0117] On the other hand, when the motor driving current I is equal toor smaller than the sublimit I1 or ranges from the sublimit I1 to thelimit I2, the control unit 35 switches to the results of comparison ofthe motor driving voltage V.

[0118] The control unit 35 determines whether the motor driving voltageV has reached the sublimit V1 (step S17). When control unit 35determines that the motor driving voltage V has reached the sublimit V1,the control unit 35 transmits a lighting signal so as to light thewarning lamp (step S18). Consequently, the control unit 35 notifies thatthe driving state of the motor 32 is approaching a state in which themotor 32 exhibits an excessive rotating speed.

[0119] Furthermore, the control unit 35 determines whether the motordriving voltage V has reached the limit V2 (step S19). When the controlunit 35 determines that the motor driving voltage V has reached thelimit V2, the control unit stops the motor 32 or inactivates the clutchso as to bring the bending section 12 to the bending operationwires-freed state in the same manner as described in relation to thedriving current I (step S16). Consequently, when the driving state ofthe motor 32 reaches the state in which the motor 32 exhibits anexcessive rotating speed, the control unit 35 does not permittransmission of driving force exerted by the motor 32 to the sprocket31.

[0120] On the other hand, when the results of comparison sent from thecomparison unit 43 b demonstrate that the motor driving current I isequal to or smaller than the sublimit I1 or ranges from the sublimit I1to the limit I2, and that the motor driving voltage V is equal to orsmaller than the sublimit V1 or ranges from the sublimit V1 to the limitV2, the control unit 35 extends control so that the bending section 12will be bent normally (step S20).

[0121] Consequently, the motor driving signal applied to the motor 32included in the electric bending endoscope 2 in accordance with thesecond embodiment is detected and compared with the pre-recorded limits.When the motor driving signal reaches the sublimit, the fact isnotified. When the motor driving signal reaches the limit, supply ofenergy to the motor 32 is stopped or transmission of power exerted bythe motor 32 is disconnected.

[0122] Consequently, the electric bending endoscope 2 in accordance withthe second embodiment provides the same advantage as the firstembodiment does.

[0123] Third Embodiment

[0124]FIG. 8 to FIG. 14 are concerned with a third embodiment of thepresent invention.

[0125] According to the first and second embodiments, the driving stateof the motor 32 is detected as a state value indicating the drivingstate of the bending drive unit 30, and compared with the recordedlimits. According to the third embodiment, the rotational position orrotating speed of the sprocket 31 is detected as the state valueindicating the driving state of the bending drive unit 30, and comparedwith recorded limits. The other constituent features are identical tothose of the first embodiment. The description of the constituentfeatures will be omitted. The components identical to those of the firstembodiment will be described with the same reference numerals assignedthereto.

[0126] As shown in FIG. 8, an electric bending endoscope system 60including the third embodiment is configured so that the rotationalposition of the sprocket 31 will be detected as a state value indicatingthe driving state of the bending drive unit 30, and compared withrecorded limits.

[0127] To be more specific, a bending control device 5C comprises: arotational position-of-sprocket detection unit (hereinafter, arotational position detection unit) 61 that detects the rotationalposition of the sprocket as a state value, which indicates the drivingstate of the bending drive unit 30 included in the electric bendingendoscope 2, from a rotational position signal sent from thepotentiometer 37; a record unit 42 c in which the limits of therotational position of the sprocket that are inputted in advance arerecorded; and a comparison unit 43 c that compares the data of therotational position of the sprocket detected by the rotational positiondetection unit 61 with the limits of the rotational position of thesprocket recorded in the record unit 42 c.

[0128] The rotational position detection unit 61 acquires the data ofthe rotational position of the sprocket from the rotational positionsignal sent from the potentiometer 37, thus receives the rotationalposition P of the sprocket, and transmits the rotational position P ofthe sprocket to the comparison unit 43 c. The rotational position P ofthe sprocket is a state value equivalent to the one indicating aposition to which the bending section 12 is bent. Moreover, therotational position P of the sprocket may be received from the encoder36.

[0129] In the record unit 42 c, a sublimit P1 immediately preceding alimit and the limit P2 that are inputted in advance are recorded as thelimits of the rotational position of the sprocket. The recorded limitsare transmitted to the comparison unit 43 c.

[0130] The comparison unit 43 c compares the rotational position P ofthe sprocket sent from the rotational position detection unit 61 withthe sublimit P1 and limit P2 read from the record unit 42 c, andtransmits the results of the comparison to the control unit 35.

[0131] The rotational position detection unit 61, record unit 42 c, andcomparison unit 43 c are connected to the control unit 35, though theconnections are not shown. The rotational position detection unit 61,record unit 42 c, and comparison unit 43 c are controlled with controlsignals sent from the control unit 35. Incidentally, the rotationalposition detection unit 61, record unit 42 c, and comparison unit 43 cmay be realized with software and installed in the control unit 35.

[0132] The control unit 35 controls, as described in the flowchart ofFIG. 9 which will be referred to later, the notification unit 44according to the results of comparison sent from the comparison unit 43c. When the driving state of the motor 32 reaches the limit, the controlunit 35 stops the motor 32 or brings the bending section 12 to thebending operation wires-freed state.

[0133] The electric bending endoscope 2 is, similarly to the onedescribed in relation to the first embodiment, connected to the lightsource device 3, video processor 4, and bending control device 5C, andused for endoscopic examination or the like.

[0134] An operator holds the grip 7 a of the electric bending endoscope2 so as to perform endoscopic examination. During the endoscopicexamination, the operator handles the bending operation input unit 20such as a joystick, or the like so as to bend the bending section 12.

[0135] When the bending section 12 of the electric bending endoscope 2is bent over a prolonged period of time, the driving state of the motor32 reaches the limit. Consequently, the sprocket 37 exerts excessivebending force, and the rotational position P of the sprocket rises. Atthis time, the electric bending endoscope 2 has the bending of thebending section 12 thereof controlled as described in the flowchart ofFIG. 9.

[0136] As described in FIG. 9, the rotational position detection unit 61measures or detects the data of the rotational position of the sprocketfrom the rotational position signal sent from the potentiometer 37, andthus receives the rotational position P of the sprocket (step S21). Inresponse to an output signal sent from the control unit 35, therotational position detection unit 61 transmits the detected rotationalposition P of the sprocket to the comparison unit 43 c.

[0137] On the other hand, from the record unit 42 c, the recordedsublimit P1 and limit P2 of the rotational position of the sprocket aretransmitted to the comparison unit 43 c in response to an output signalsent from the control unit 35.

[0138] The comparison unit 43 c compares the rotational position P ofthe sprocket sent from the rotational position detection unit 61 withthe sublimit P1 and limit P2 read from the record unit 42 c, andtransmits the results of the comparison to the control unit 35.

[0139] The control unit 35 determines based on the results of comparisonsent from the comparison unit 43 c whether the rotational position P ofthe sprocket has reached the sublimit P1 (step S22). When the controlunit 35 determines that the rotational position P of the sprocket hasreached the sublimit P1, the control unit 35 transmits a lighting signalso as to light the warning lamp (step S23). Thus, the control unit 35notifies that the driving state of the motor 32 is approaching the limitand the sprocket 37 is beginning to exert excessive bending force.

[0140] Furthermore, the control unit 35 determines whether therotational position P of the sprocket has reached the limit P2 (stepS24). When the control unit 35 determines that the rotational position Pof the sprocket has reached the limit P2, the control unit 35 stops themotor 32 or inactivates the clutch so as to bring the bending section 12to the bending operation wires-freed state (step S25) in the same manneras described in relation to the first embodiment. Thus, when the drivingstate of the motor 32 reaches the limit and the sprocket 37 exertsexcessive bending force, the control unit 35 does not permittransmission of driving force exerted by the motor 32 to the sprocket31.

[0141] On the other hand, when the results of comparison sent from thecomparison unit 43 c demonstrate that the rotational position P of thesprocket is equal to or smaller than the sublimit P1 or ranges from thesublimit P1 to the limit P2, the control unit 35 extends control so thatthe bending section 12 will be bent normally (step S26).

[0142] Consequently, the rotational position of the sprocket 31incorporated in the electric bending endoscope 2 in accordance with thethird embodiment is detected and compared with the pre-recorded limits.When the rotational position of the sprocket reaches the sublimit, thefact is notified. When the rotational position of the sprocket reachesthe limit, supply of energy to the motor 32 is stopped or transmissionof power exerted by the motor 32 is disconnected.

[0143] Consequently, the electric bending endoscope 2 in accordance withthe third embodiment provides the same advantage as the first embodimentdoes.

[0144] Alternatively, the rotating speed of the sprocket 31 incorporatedin the electric bending endoscope may be detected as a state valueindicating the driving state of the bending drive unit 30 and comparedwith recorded limits.

[0145] Specifically, an electric bending endoscope system 70 is, asshown in FIG. 10, configured so that the rotating speed of the sprocket31 will be detected as the state value indicating the driving state ofthe bending drive unit 30 and compared with a recorded range of limits.

[0146] To be more specific, a bending control device 5D comprises: arotating speed-of-sprocket detection unit (hereinafter, a rotating speeddetection unit) 71 that detects the rotating speed of the sprocket as astate value, which indicates the driving state of the bending drive unit30 included in the electric bending endoscope 2, from a rotatingposition signal sent from the potentiometer 37; a record unit 42 d inwhich the limits of the rotating speed of the sprocket that are inputtedin advance are recorded; and a comparison unit 43 d that compares thedata of the rotating speed of the sprocket detected by the rotatingspeed detection unit 71 with the limits of the rotating speed of thesprocket recorded in the record unit 42 d.

[0147] The rotating speed detection unit 71 acquires the data of therotational position of the sprocket from the rotational position signalsent from the potentiometer 37, and thus receives the rotationalposition P of the sprocket. The rotating speed detection unit 71 thencalculates the time derivative of the rotational position P of thesprocket so as to work out a rotating speed V of the sprocket, and thentransmits the rotating speed V of the sprocket to the comparison unit 43d. The rotating speed V of the sprocket is a state value equivalent tothe one indicating the bending speed of the bending section 12.Moreover, the rotational position P of the sprocket may be received fromthe encoder 36.

[0148] In the record unit 42 d, a sublimit V1 immediately preceding alimit and the limit V2 that are inputted in advance are recorded as thelimits of the rotating speed of the sprocket. The recorded limits aretransmitted to the comparison unit 43 d.

[0149] The comparison unit 43 d compares the rotating speed V of thesprocket sent from the rotating speed detection unit 71 with thesublimit V1 and limit V2 read from the record unit 42 d, and transmitsthe results of the comparison to a control unit 35.

[0150] The rotating speed detection unit 71, record unit 42 d, andcomparison unit 43 d are connected to the control unit 35, though theconnections are not shown. The rotating speed detection unit 71, recordunit 42 d, and comparison unit 43 d are controlled with control signalssent from the control unit 35. Incidentally, the rotating speeddetection unit 71, record unit 42 d, and comparison unit 43 d may berealized with software and installed in the control unit 35.

[0151] The control unit 35 controls, as described in the flowchart ofFIG. 11 that will be referred to later, the notification unit 44according to the results of comparison sent from the comparison unit 43d. When the rotating speed of the sprocket reaches the limit, thecontrol unit 35 stops the motor 32 or brings the bending section 12 tothe bending operation wires-freed state.

[0152] The electric bending endoscope 2 is, similarly to the onedescribed in relation to the first embodiment, connected to the lightsource device 3, video processor 4, and bending control device 5D, andused for endoscopic examination or the like.

[0153] An operator holds the grip 7 a of the electric bending endoscope2 so as to perform endoscopic examination. During the endoscopicexamination, the operator handles the bending operation input unit 20such as a joystick, or the like so as to bend the bending section 12.

[0154] Herein, when the bending section 12 of the electric bendingendoscope 2 is bend over a prolonged period of time, the driving stateof the motor 32 reaches the limit. The sprocket 37 exerts excessivebending force and the rotating speed V of the sprocket rises. At thistime, the electric bending endoscope 2 has the bending of the bendingsection 12 thereof controlled as described in the flowchart of FIG. 11.

[0155] As described in FIG. 11, the rotating speed detection unit 71acquires the data of the rotating speed of the sprocket from a rotatingposition signal sent from the potentiometer 37, and thus measures ordetects the rotating speed V of the sprocket (step S31). In response toan output signal sent from the control unit 35, the rotating speeddetection unit 71 transmits the detected rotating speed V of thesprocket to the comparison unit 43 d.

[0156] On the other hand, from the record unit 42 d, the recordedsublimit V1 and limit V2 of the rotating speed of the sprocket aretransmitted to the comparison unit 43 d in response to an output signalsent from the control unit 35.

[0157] The comparison unit 43 d compares the rotating speed V of thesprocket sent from the rotating speed detection unit 71 with thesublimit V1 and limit V2 read from the record unit 42 d, and transmitsthe results of the comparison to the control unit 35.

[0158] The control unit 35 determines based on the results of comparisonsent from the comparison unit 43 d whether the rotating speed V of thesprocket has reached the sublimit V1 (step S32). When the control unit35 determines that the rotating speed V of the sprocket has reached thesublimit V1, the control unit 35 transmits a lighting signal so as tolight the warning lamp (step S33). Thus, the control unit 35 notifiesthat the driving state of the motor 32 is approaching the limit and thesprocket 37 is beginning to bring about an excessive bending speed.

[0159] Furthermore, the control unit 35 determines whether the rotatingspeed V of the sprocket has reached the limit V2 (step S34). When thecontrol unit 35 determines that the rotating speed V of the sprocket hasreached the limit V2, the control unit 35 stops the motor 32 orinactivates the clutch so as to bring the bending section 12 to thebending operation wires-freed state (step S35) in the same manner asdescribed in relation to the first embodiment. Consequently, when thedriving state of the motor 32 reaches the limit and the sprocket 37brings about an excessive bending speed, the control unit 35 does notpermit transmission of driving force exerted by the motor 32 to thesprocket 31.

[0160] On the other hand, when the results of comparison sent from thecomparison unit 43 d demonstrate that the rotating speed V of thesprocket is equal to or smaller than the sublimit V1 or ranges from thesublimit V1 to the limit V2, the control unit 35 extends control so thatthe bending section 12 will be bent normally (step S36).

[0161] Consequently, the rotating speed of the sprocket 31 incorporatedin the electric bending endoscope 2 of the present variant is detectedand compared with the pre-recorded limits. When the rotating speed ofthe sprocket reaches the sublimit, the fact is notified. When therotating speed of the sprocket reaches the limit, supply of energy tothe motor 32 is stopped or transmission of power exerted by the motor 32is disconnected.

[0162] Consequently, the electric bending endoscope 2 in accordance withthe present variant provides the same advantage as the third embodimentdoes.

[0163] Alternatively, a motor driving signal sent from the motoramplifier 34 may be controlled.

[0164] Specifically, a predetermined rotating speed V3 of the sprocketis inputted and recorded in the record unit 42 d in advance. Thecomparison unit 43 d compares the rotating speed V of the sprocket sentfrom the rotating speed detection unit 71 with the recorded rotatingspeed of the sprocket. Based on the results of the comparison, thecontrol unit 35 controls the motor driving signal to be sent from themotor amplifier 34. In other words, the control unit 35 controls themotor driving signal to be sent from the motor amplifier 34 so that thebending speed at which the bending section 12 is bent will remainconstant as shown in FIG. 12.

[0165] In this case, when the results of comparison sent from thecomparison unit 43 d demonstrate that the rotating speed V of thesprocket has reached the predetermined rotating speed of the sprocket,the control unit 35 controls the motor amplifier 34 so that the rotatingspeed V of the sprocket will equal the predetermined rotating speed ofthe sprocket.

[0166] Consequently, according to the present variant, the rotatingspeed V of the sprocket can be suppressed to the predetermined rotatingspeed. The bending section 12 will therefore, not be bent withoutoperator's intention.

[0167] Otherwise, a bending operation speed signal produced by thebending operation input unit 20 included in the electric bendingendoscope may be controlled.

[0168] Specifically, the control unit 35 controls the bending operationinput unit 20 so that the bending operation speed signal produced by thebending operation input unit 20 such as a joystick, or the like willremain constant as shown in FIG. 13. When a handling speed at which thebending operation input unit 20 is handled reaches a predeterminedhandling speed, the control unit 35 controls the bending operation inputunit 20 so that the bending operation speed signal produced by thebending operation input unit 20 will be equal to a predetermined bendingoperation speed signal.

[0169] In this case, as shown in FIG. 14, an electric bending endoscopesystem 80 is configured so that a handling speed at which the bendingoperation input unit 20 is handled will be measured or detected using apotentiometer that is not shown. A handling speed detection unit 81included in a bending control unit 5E acquires the data of the handlingspeed. The handling speed is then compared with a recorded predeterminedhandling speed.

[0170] Specifically, a predetermined handling speed at which the bendingoperation input unit 20 included in the electric bending endoscope 2 ishandled is inputted in advance and recorded in a record unit 42 e. Acomparison unit 43 e compares the recorded handling speed with thehandling speed sent from the handling speed detection unit 81. Based onthe results of the comparison, the control unit 35 controls a bendingoperation speed signal sent from the bending operation input unit 20.

[0171] Consequently, according to the present variant, a handling speedsignal sent from the bending operation input unit 20 can be suppressedto a predetermined bending operation speed signal. The bending section12 will not be bent without operator's intention.

[0172] Fourth Embodiment

[0173]FIG. 15 to FIG. 17 are concerned with a fourth embodiment of thepresent invention.

[0174] According to the fourth embodiment, positions to which thebending operation wires 26 are bent are detected as state valuesindicating the driving state of the bending drive unit 30, and comparedwith recorded limits. The other constituent features are identical tothose of the first embodiment. The description of the constituentfeatures will be omitted. Components identical to those of the firstembodiment will be described with the same reference numerals assignedthereto.

[0175] As shown in FIG. 15, an electric bending endoscope system 90including the fourth embodiment is configured so that positions to whichthe bending operation wires 26 are bent will be detected as state valuesindicating the driving state of the bending drive unit 30 and comparedwith recorded limits.

[0176] To be more specific, the electric bending endoscope 2 has adisplacement-of-bending operation wire sensor (hereinafter, adisplacement sensor) 91, which detects the positions to which thebending operation wires 26 are bent as state values indicating thedriving state of the bending drive unit 30, incorporated in the flexibletube 13 thereof. A bending control device 5F comprises: aposition-of-wire detection unit 92 that receives the data of thepositions to which the bending operation wires are bent that aredetected by the displacement sensor 91; a record unit 42 f in which thelimits of the positions to which the bending operation wires are bentthat are inputted in advance are recorded; and a comparison unit 43 fthat compares the data of the positions, to which the bending operationwires are bent that are detected by the position-of-wire detection unit92, with the limits of the positions to which the bending operationwires are bent that are recorded in the record unit 42 f.

[0177] The position-of-wires detection unit 92 receives the data of thepositions to which the bending operation wires are bent, which aredetected by the displacement sensor 91, as the bent positions P, andtransmits the bent positions P to the comparison unit 43 f.Incidentally, the bent positions P are state values equivalent to theone indicating an angle by which the bending section 12 is bent.

[0178] In the record unit 42 f, a sublimit P1 immediately preceding alimit and the limit P2 that are inputted in advance are recorded as thelimits of the positions to which the bending operation wires are bent.The recorded limits are transmitted to the comparison unit 43 f.

[0179] The comparison unit 43 f compares the bent position P sent fromthe position-of-wire detection unit 92 with the sublimit P1 and limit P2read from the record unit 42 f, and transmits the results of thecomparison to the control unit 35.

[0180] The position-of-bending operation wire detection unit 91, recordunit 42 f, and comparison unit 43 f are connected to the control unit35, though the connections are not shown. The position-of-bendingoperation wire detection unit 91, record unit 42 f, and comparison unit43 f are controlled with control signals sent from the control unit 35.Incidentally, the position-of-bending operation wire detection unit 91,record unit 42 f, and comparison unit 43 f may be realized with softwareand installed in the control unit 35.

[0181] The control unit 35 controls, as described in the flowchart ofFIG. 17 that will be described later, the notification unit 44 accordingto the results of comparison sent from the comparison unit 43 f. Whenthe positions to which the bending operation wires 26 are bent reach thelimit, the control unit 35 stops the motor 32 or brings the bendingsection 12 to the bending operation wires-freed state.

[0182] Next, referring to FIG. 16, the displacement sensor 91incorporated in the flexible tube 13 will be described below.

[0183] As shown in FIG. 16, the displacement sensor 91 has sensor coilsincorporated in coil sheaths 93 through which the respective bendingoperation wires 26 lie and which guide the bending operation wires. Acoil wire used to create the coil sheaths 93 is made of alow-permeability magnetic substance such as a stainless steel ortungsten or a non-magnetic substance. The bending operation wires 26 arealso made of a similar low-permeability magnetic substance ornon-magnetic substance.

[0184] The coil sheath 93 has part of the coil wire, which is locatednear the distal end thereof,. removed. A thin pipe 94 made of alow-permeability magnetic substance such as a stainless steel or anon-magnetic substance is fitted in the removed part of the coil sheath93. The pipe 94 is arranged coaxially to the coil sheath 93. The distaland rear ends of the pipe 94 are spliced to the coil wire of the coilsheath 93. Thus, the pipe 94 is integrated with the coil sheath 93 inorder to form a guide sheath. The pipe 94 does not interrupt movement ofeach bending operation wire 26. The pipe 94 is also made of a similarlow-permeability magnetic substance or non-magnetic substance. Moreover,the pipe 94 is so thin as to be bent. The pipe 94 as well as the coilsheath 93 will not impair the flexibility of the flexible tube.

[0185] The pipe 94 is sheathed with a sensor coil 95. The sensor coil 95is wound about the pipe 94 while being electrically isolated therefrom.An insulating material or the like may be applied to the periphery ofthe sensor coil 95.

[0186] The sensor coil 95 has leads 97 extended from both the endsthereof. The leads 97 are led to the angling connector 9 c of theuniversal cord 8, and then led to the position-of-wire detection unit 92included in the bending control device 5 over the connection cable 5 a.Incidentally, the position-of-wire detection unit 92 applies analternating voltage to the sensor coils 95. A resonant capacitor that isnot shown is used to detect a change in a voltage across both the endsof each of the sensor coils. This realizes an inductance detection unitthat detects a change in inductance offered by each of the sensor coils95 in the form of a change in voltage.

[0187] Parts of the bending operation wires 26 that meet the sensorcoils 95 have the peripheries thereof coated with a magnetic material 98and are thus formed as magnetic parts 98. For formation of the magneticparts 98, the bending operation wires 26 must not be thick. Therefore,the bending operation wires 26 have a small-diameter part 99 formed overa certain length along the axis of each wire. The peripheries of thesmall-diameter parts 99 are coated with the magnetic material.

[0188] The displacement sensor 91 has the foregoing components. Herein,when the bending section 12 is bent, the bending operation wires 26 aredrawn or released similarly to those described in relation to the firstembodiment. Consequently, the magnetic parts 98 move within therespective sensor coils 95. This causes a permeability to change.Accordingly, the inductance offered by each of the sensor coils 95included in the displacement sensor 91 changes, and the voltage acrossboth the ends of the sensor coil 95 varies. Eventually, the positions towhich the bending operation wires 26 are bent are detected as an outputto be sent to the position-of-wire detection unit 92.

[0189] The electric bending endoscope 2 is, similarly to the onedescribed in relation to the first embodiment, connected to the lightsource device 3, video processor 4, and bending control device 5F, andused for endoscopic examination or the like.

[0190] An operator holds the grip 7 a of the electric bending endoscope2 so as to perform endoscopic examination. During the endoscopicexamination, the operator handles the bending operation input unit 20such as a joystick, or the like so as to bend the bending section 12.

[0191] When the bending section of the electric bending endoscope 2 isbent over a prolonged period of time, the driving state of the motor 32approaches the limit. The bent positions P to which the bendingoperation wires 26 are bent imply excessive bending operation. At thistime, the electric bending endoscope 2 has the bending section 12thereof controlled as described in the flowchart of FIG. 17.

[0192] As described in FIG. 17, the position-of-wire detection unit 92measures or detects as the bent positions P the data of the positions towhich the bending operation wires are bent that is sent from thedisplacement sensor 91 (step S41). The position-of-wire detection unit92 then transmits the detected bent positions P to the comparison unit43 f in response to an output signal sent from the control unit 35.

[0193] On the other hand, from the record unit 42 f, the recordedsublimit P1 and limit P2 of the positions to which the bending operationwires are bent are transmitted to the comparison unit 43 f in responseto an output signal sent from the control unit 35.

[0194] The comparison unit 43 f compares the bent positions P, which aresent from the position-of-wire detection unit 92, with the sublimit P1and limit P2 read from the record unit 42 f, and transmits the resultsof the comparison to the control unit 35.

[0195] The control unit 35 determines based on the results of comparisonsent from the comparison unit 43 f whether the bent positions P havereached the sublimit P1 (step S42). When the control unit determinesthat the bent positions P have reached the sublimit P1, the control unit35 transmits a lighting signal so as to light the warning lamp (stepS43). Thus, the control unit 35 notifies that the driving state of themotor 32 is approaching the limit and the bent positions P are beginningto imply excessive bending operation.

[0196] Furthermore, the control unit 35 determines whether the bentpositions P have reached the limit P2 (step S44). When control unit 35determines that the bent positions P have reached the limit P2, thecontrol unit 35 stops the motor 32 or inactivates the clutch so as tobring the bending section 12 to the bending operation wires-freed statein the same manner as the one described in relation to the firstembodiment (step S45). Consequently, when the driving state of the motor32 reaches the limit and the bent positions P to which the bendingoperation wires 26 are bent imply excessive bending operation, thecontrol unit 35 does not permit transmission of driving force exerted bythe motor 32 to the sprocket 31.

[0197] On the other hand, when the results of comparison sent from thecomparison unit 43 f demonstrate that the bent positions P are equal toor smaller than the sublimit P1 or ranges from the sublimit P1 to thelimit P2, the control unit 35 extends control so that the bendingsection 12 will be bent normally (step S46).

[0198] Consequently, the positions to which the bending operation wires26 incorporated in the electric bending endoscope 2 in accordance withthe fourth embodiment are bent are detected and compared with thepre-recorded limits. When the positions to which the bending operationwires are bent reach the sublimit, the fact is notified. When thepositions to which the bending operation wires are bent reach the limit,supply of energy to the motor 32 is stopped or transmission of powerexerted by the motor 32 is disconnected.

[0199] The electric bending endoscope 2 in accordance with the fourthembodiment provides the same advantage as the one of the firstembodiment.

[0200] Fifth Embodiment

[0201]FIG. 18 to FIG. 23B are concerned with a fifth embodiment of thepresent invention.

[0202] According to the fourth embodiment, the positions to which thebending operation wires 26 are bent are detected as state valuesindicating the driving state of the bending drive unit 30, and comparedwith the recorded limits. According to the fifth embodiment, thetensions of the bending operation wires 26 are detected as state valuesindicating the driving state of the bending drive unit 30, and comparedwith recorded limits. The other constituent features are identical tothose concerning the first embodiment. The description of theconstituent features will be omitted. Components identical to thoseconcerning the first embodiment will be described with the samereference numerals assigned thereto.

[0203] A shown in FIG. 18, an electric bending endoscope system 100including the fifth embodiment is configured so that the tensions of thebending operation wires 26 will be detected as state values indicatingthe driving state of the bending drive unit 30, and compared withrecorded limits.

[0204] To be more specific, the electric bending endoscope 2 includes atension-of-bending operation wire sensor (hereinafter, tension sensor)101 incorporated in the distal section 11 thereof. The tension sensor101 detects the tensions of the bending operation wires 26 as statevalues indicating the driving state of the bending drive unit 30. Abending control device 5G includes: a tension detection unit 102 thatacquires the data of the tensions detected by the tension sensors 101; arecord unit 42 g in which the limits of tension that are inputted inadvance are recorded; and a comparison unit 43 g that compares the dataof the tensions sent from the tension detection unit 102 with the limitsof tension recorded in the record unit 42 g.

[0205] The tension detection unit 102 acquires the data of the tensionsdetected by the tension sensor 101 as tensions T, and transmits thetensions T to the comparison unit 43 g.

[0206] In the record unit 42 g, a sublimit T1 immediately preceding alimit and the limit T2 that are inputted in advance are recorded as thelimits of tension. The recorded limits are transmitted to the comparisonunit 43 g.

[0207] The comparison unit 43 g compares the tensions T sent from thetension detection unit 102 with the sublimit T1 and limit T2 read fromthe record unit 42 g, and transmits the results of the comparison to thecontrol unit 35.

[0208] The tension detection unit 91, record unit 42 g, and comparisonunit 43 g are connected to the control unit 35, though the connectionsare not shown. The tension detection unit 91, record unit 42 g, andcomparison unit 43 g are controlled based on control signals sent fromthe control unit 35. Incidentally, the tension detection unit 91, recordunit 42 g, and comparison unit 43 g may be realized with software andinstalled in the control unit 35.

[0209] The control unit 35 controls, as described in the flowchart ofFIG. 20 that will be referred to later, the notification unit 44according to the results of comparison sent from the comparison unit 43g. When the tensions of the bending operation wires 26 reach the limit,the control unit stops the motor 32 or brings the bending section 12 tothe bending operation wires-freed state.

[0210] Next, referring to FIG. 19A and FIG. 19B, the tension sensor 101incorporated in the distal section 11 will be described below.

[0211] As shown in FIG. 19A and FIG. 19B, the tension sensor 101 isincorporated in the distal section 11 coupled to the distal end of thebending section 12. The tension sensor 101 has mounting holes 103 formedin an axial direction along the periphery of the distal section 11 sothat the four bending operation wires 26 will be passed through therespective mounting holes 103. A pair of locking rings 104 a and 104 bfitted in each of the mounting holes 103 while being separated from eachother in the axial direction. A strain generator 105 realized with athin cylinder is sandwiched between the locking rings 104 a and 104 b.

[0212] The locking rings 104 a and 104 b and the strain generator 105have one of the bending operation wires 26 penetrated through them. Eachof the bending operation wires 26 has the distal end thereof locked inthe locking ring 104 a. Furthermore, the strain generator 105 has astrain gauge 106 fixed to the periphery thereof.

[0213] The tension sensor 101 has the foregoing components. When thebending section 12 is bent, the bending operation wires 26 are drawn orreleased in the same manner as described in relation to the firstembodiment. Consequently, the strain generators 105 are tensed andcompressed in the axial direction. A strain is generated. The straingauges 106 included in the tension sensor 101 detect degrees of strains,that is, the tensions of the bending operation wires 26.

[0214] The data of the tensions detected by the tension sensor 101 is,similarly to the counterpart detected in the fourth embodiment,transmitted to the tension detection unit 102 included in the bendingcontrol unit 5G over a signal line that is not shown. The data of thetensions is received as tensions T.

[0215] The electric bending endoscope 2 having the foregoing structureis, similarly to the one described in relation to the first embodiment,connected to the light source device 3, video processor 4, and bendingcontrol device 5F, and used for endoscopic examination or the like.

[0216] An operator holds the grip 7 a of the electric bending endoscope2 so as to perform endoscopic examination. During the endoscopicexamination, the operator handles the bending operation input unit 20such as a joystick, or the like so as to bend the bending section 12.

[0217] When the bending section of the electric bending endoscope 2 isbent over a prolonged period of time, the driving state of the motor 32approaches the limit. The tensions T of the bending operation wires 26bring about excessive bending force. At this time, the electric bending.endoscope 2 has the bending of the bending section 12 thereof controlledas described in the flowchart of FIG. 20.

[0218] As described in FIG. 20, the tension detection unit 102 measuresor detects the data of tensions sent from the tension sensor 101 astensions T (step S51), and transmits the detected tensions T to thecomparison unit 43 g in response to an output signal sent from thecontrol unit 35.

[0219] On the other hand, from the record unit 42 g, the recordedsublimit T1 and limit T2 of tension are transmitted in response to anoutput signal sent from the control unit 35.

[0220] The comparison unit 43 g compares the tensions T sent from thetension detection unit 102 with the sublimit T1 and limit T2 read fromthe record unit 42 g, and transmits the results of the comparison to thecontrol unit 35.

[0221] The control unit 35 determines based on the results of comparisonsent from the comparison unit 43 g whether the tensions T have reachedthe sublimit T1 (step S52). When the control unit 35 determines that thetensions T have reached the sublimit T1, the control unit 35 transmits alighting signal so as to light the warning lamp (step S53). Thus, thecontrol unit 35 notifies that the driving state of the motor 32 isapproaching the limit and the tensions T of the bending operation wires26 are beginning to bring about excessive bending force.

[0222] Furthermore, the control unit 35 determines whether the tensionsT have reached the limit T2 (step S54). When the control unit 35determines that the tensions T have reached the limit T2, the controlunit 35 stops the motor 32 or inactivates the clutch so as to bring thebending section 12 to the bending operation wires-freed state in thesame manner as the one described in relation to the first embodiment(step S55). Consequently, when the driving state of the motor 32 reachesthe limit and the tensions T of the bending operation wires 26 bringabout excessive bending force, the control unit 35 does not permittransmission of driving force exerted by the motor 32 to the sprocket31.

[0223] On the other hand, when the results of comparison sent from thecomparison unit 43 g demonstrate that the tensions T are equal to orlower than the sublimit T1 or range from the sublimit T1 to the limitT2, the control unit 35 extends control so that the bending section 12will be bent normally (step S56).

[0224] Consequently, the tensions of the bending operation wires 26included in the electric bending endoscope 2 in accordance with thefifth embodiment are detected and compared with the pre-recorded limits.When the tensions reach the sublimit, the fact is notified. When thetensions reach the limit, supply of energy to the motor 32 is stopped ortransmission of power exerted by the motor 32 is disconnected.

[0225] Consequently, the electric bending endoscope 2 in accordance withthe fifth embodiment provides the same advantage as the first embodimentdoes.

[0226] The tension sensor may be structured as shown in FIG. 21A or FIG.21B.

[0227] As shown in FIG. 21A, a tension sensor 101B has strain generators105 thereof realized with piezoelectric devices 110 but does not includethe strain gauges 106.

[0228] When the bending section 12 is bent, the bending operation wires26 are drawn or released in the same manner as described in relation tothe first embodiment. The strain generators 105 included in the tensionsensor 101B are tensed, and then compressed in an axial direction. Thiscauses a strain. A voltage is then developed in the piezoelectricdevices 110 included in the tension sensor 101B. The developed voltagesare transmitted to the tension detection unit 102, whereby the tensionsof the bending operation wires 26 can be detected.

[0229] As shown in FIG. 21B, a tension sensor 101C has a pair ofelectrode plates 111 a and 111 b at both ends of each strain generator105.

[0230] When the bending section 12 is bent, the bending operation wires26 are drawn or released in the same manner as described in relation tothe first embodiment. The strain generators 105 included in the tensionsensor 10C are then tensed, and compressed in an axial direction. Thiscauses a strain. The distance between each pair of electrode plates 111a and 111 b changes, whereby an electrostatic capacitance-dependentvoltage varies. The variations of the voltages are transmitted to thetension detection unit 102. Consequently, the tensions of the bendingoperation wires 26 can be detected.

[0231] Moreover, the tension sensor may be structured as shown in FIG.22A and FIG. 22B.

[0232] As shown in FIG. 22A and FIG. 22B, a tension sensor 101D has anotch 112, which is shaped substantially like a bracket, formed in partsof the leading bending piece 25 a that meet the respective bendingoperation wires 26. A tongue-like wire coupler 113 is enclosed in eachof the notches 112 included in the tension sensor 101D, and has a neck113 a and a head 113 b. The distal part of each of the bending operationwires 26 is coupled to the head 113 of each of the wire couplers 113included in the tension sensor 101D. Moreover, a strain gauge 114 isattached to each of the necks 113 a.

[0233] When the bending section 12 is bent, the bending operation wires26 are drawn or released in the same manner as described in relation tothe first embodiment. The wire couplers 113 included in the tensionsensor 101D are then tensed. Consequently, the necks 113 a are strained.The strain gauges 114 included in the tension sensor 101D detect degreesof strains, that is, the tensions of the bending operation wires 26.

[0234] The tension sensor may be structured as shown in FIG. 23A andFIG. 23B.

[0235] As shown in FIG. 23A and FIG. 23B, a joint tube 115 that is ajoint of the flexible tube 13 and bending section 12 has asmall-diameter portion 115 a extended in the middle thereof in an axialdirection. An opening window 116 is formed at positions on the outerwall of the small-diameter portion 115 a corresponding to the positionsof the respective bending operation wires 26. The formation of theopening windows 116 provides the small-diameter portion 115 a withstrain generators 117.

[0236] Moreover, a strain gauge 118 is disposed near each of the openingwindows 116 of the strain generators 117 included in the tension sensor101E.

[0237] The tension sensor 101E has the foregoing structure. When thebending section 12 is bent, the bending operation wires 26 are drawn orreleased in the same manner as the ones described in relation to thefirst embodiment. The strain generators 117 located near the respectivebending operation wires 26 are compressed. Consequently, the straingenerators 117 deflect and strain. The strain gauges 118 detect thedegrees of strains, that is, the tensions of the bending operation wires26.

[0238] Sixth Embodiment

[0239]FIG. 24 and FIG. 25 are concerned with a sixth embodiment of thepresent invention.

[0240] According to the sixth embodiment, the mechanical service life ofthe motor 32 is detected as a state value indicating the driving stateof the bending drive unit 30, and compared with recorded limits. Theother constituent features are identical to those of the firstembodiment. The description of the constituent features will thereforebe omitted. Components identical to those of the first embodiment willbe described with the same reference numerals assigned thereto.

[0241] As shown in FIG. 24, an electric bending endoscope system 120including the sixth embodiment is configured so that the mechanical usetime of the motor 32 will be detected as a state value indicating thedriving state of the bending drive unit 30 and compared with recordedlimits.

[0242] To be more specific, the electric bending endoscope 2 has aservice life detection unit 121 and a service life record unit 122incorporated in the angling connector 9 c thereof. The service lifedetection unit 121 detects the mechanical use time of the motor 32 as astate value indicating the driving state of the bending drive unit 30.The mechanical use time of the motor 32 detected by the service lifedetection unit 121 and the limits of mechanical use time inputted inadvance are recorded in the service life record unit 122. A bendingcontrol device 5H includes a comparison unit 43 h that compares the dataof the mechanical use time detected by the service life detection unit121 with the limits of mechanical use time recorded in the service liferecord unit 122.

[0243] Furthermore, the bending control device 5H includes acurrent/voltage detection unit 123 that detects a current and a voltagewhich serve as a motor driving signal to be sent from the motoramplifier 34. The data of the detected current and voltage are receivedas a current i and a voltage v respectively, and transmitted to theservice life detection unit 121.

[0244] The service life detection unit 121 calculates a mechanical usetime LT from the current i and voltage v sent from the current/voltagedetection unit 123 and a use time Δt. The previous mechanical use timeLT is updated with the calculated value, and the calculated value istransmitted to the comparison unit 43 h. Incidentally, the mechanicaluse time may be calculated from the tension T, which is provided by thetension sensor 101 and tension detection unit 102 as described inrelation to the fifth embodiment, and the use time Δt.

[0245] In the service life record unit 122, a sublimit LT1 immediatelypreceding a limit and the limit L2 that are inputted in advance arerecorded as the limits of mechanical use time. The recorded limits aretransmitted to the comparison unit 43 h.

[0246] The comparison unit 43 h compares the mechanical use time LT sentfrom the service life detection unit 121 with the sublimit LT1 and limitLT2 read from the service life record unit 122, and transmits theresults of the comparison to the control unit 35.

[0247] The service life detection unit 121, service life record unit122, comparison unit 43 h, and current/voltage detection unit 123 areconnected to the control unit 35, though the connections are not shown.The service life detection unit 121, service life record unit 122,comparison unit 43 h, and current/voltage detection unit 123 arecontrolled based on control signals sent from the control unit 35.Incidentally, the service life detection unit 121, service life recordunit 122, comparison unit 43 h, and current/voltage detection unit 123may be realized with software and installed in the control unit 35.

[0248] Moreover, the service life record unit 122 may be incorporated inthe bending control device 5H. The mechanical use time LT that differsfrom endoscope to endoscope, and the sublimit LT1 and limit LT2 may berecorded in the service life record unit 122.

[0249] The control unit 35 controls, as described in the flowchart ofFIG. 25 that will be referred to later, the notification unit 44according to the results of comparison sent from the comparison unit 43h. When the mechanical use time of the motor 32 reaches the limit, thecontrol unit 35 stops the motor 32 or brings the bending section 12 tothe bending operation wires-freed state.

[0250] The electric bending endoscope 2 having the above components is,similarly to the one in accordance with the first embodiment, connectedto the light source device 3, video processor 4, and bending controldevice 5H, and used for endoscopic examination or the like.

[0251] An operator holds the grip 7 a of the electric bending endoscope2 so as to perform an endoscopic examination. During the endoscopicexamination, the operator handles the bending operation input unit 20such as a joystick, or the like so as to bend the bending section 12.

[0252] When the bending section 12 of the electric bending endoscope 2is bent over a prolonged period of time, the defined use time of themotor 32 approaches the limit. At this time, the electric bendingendoscope 2 has the bending of the bending section 12 thereof controlledas described in the flowchart of FIG. 25.

[0253] As shown in FIG. 25, the current/voltage detection unit 123measures or detects the current and voltage that serve as the motordriving signal sent from the motor amplifier 34 (step S61). Thecurrent/voltage detection unit 123 receives the data of the detectedcurrent and voltage as a current i and a voltage v, and transmits thecurrent i and voltage v to the service life detection unit 121 inresponse to an output signal sent from the control unit 35.

[0254] The service life detection unit 121 calculates the mechanical usetime LT from the current i and voltage v sent from the current/voltagedetection unit 123 and the use time Δt, and updates the previousmechanical use time LT (step S62). The service life detection unit 121then transmits the new mechanical use time LT to the comparison unit 43h in response to an output signal sent from the control unit 35.

[0255] On the other hand, from the service life record unit 122, therecorded sublimit LT1 and limit LT2 of mechanical use time aretransmitted to the comparison unit 43 h in response to an output signalsent from the control unit 35.

[0256] The comparison unit 43 h then compares the mechanical use time LTsent from the service life detection unit 121 with the sublimit LT1 andlimit LT2 read from the service life record unit 122, and transmits theresults of comparison to the control unit 35.

[0257] The control unit 35 determines based on the results of comparisonsent from the comparison unit 43 h whether the mechanical use time LThas reached the sublimit LT1 (step S63). When the control unit 35determines that the mechanical use time LT has reached the sublimit LT1,the control unit transmits a lighting signal so as to light the warninglamp (step S64). Consequently, the control unit 35 notifies that themechanical use time of the motor 32 is approaching the limit.

[0258] The control unit 35 determines whether the mechanical use time LThas reached the limit LT2 (step S65). When the control unit 35determines that the mechanical use time LT has reached the limit LT2,the control unit 35 stops the motor 32 or inactivates the clutch so asto bring the bending section 12 to the bending operation wires-freedstate in the same manner as described in relation to the firstembodiment (step S66). Consequently, when the mechanical use time of themotor 32 reaches the limit, the control unit 35 does not permittransmission of driving force exerted by the motor 32 to the sprocket31.

[0259] On the other hand, when the results of comparison sent from thecomparison unit 43 h demonstrate that the mechanical use time LT isequal to or smaller than the sublimit LT1 or ranges from the sublimitLT1 to the limit LT2, the control unit 35 extends control so that thebending section 12 will be bent normally (step S67).

[0260] The mechanical service life of the motor 32 incorporated in theelectric bending endoscope 2 in accordance with the sixth embodiment isdetected and compared with the pre-recorded limits. When the mechanicalservice life reaches the sublimit, the fact is notified. When themechanical service life reaches the limit, supply of energy to the motor32 is stopped or transmission of power exerted by the motor 32 isdisconnected.

[0261] Consequently, the electric bending endoscope 2 in accordance withthe sixth embodiment provides the same advantage as the first embodimentdoes.

[0262] According to the present invention, it is apparent that a widerange of different embodiments can be formed based on the inventionwithout a departure from the spirit and scope of the invention. Thepresent invention will be limited to the appended claims but notrestricted to any specific embodiments.

What is claimed is:
 1. The electric bending endoscope comprising: anelongated insertion unit; a bending section formed adjacently to adistal section of the insertion unit; a bending drive unit for drivingthe bending section to bend; a bending operation input unit for use ininstructing bending of the bending section; a state detection unit fordetecting the driving state of the bending drive unit; a record unit inwhich the limits of abilities of the bending drive unit are recorded; acomparison unit for comparing the driving state detected by the statedetection unit with the limits recorded in the record unit; and acontrol unit for when the results of comparison sent from the comparisonunit demonstrate that the driving state of the bending drive unit hasreached the limit, notifying a user of the driving state of the bendingdrive.
 2. The electric bending endoscope according to claim 1, whereinwhen the results of comparison sent from the comparison unit demonstratethat the driving state of the bending drive unit has reached the limit,the control unit stops supply of energy to the bending drive unit. 3.The electric bending endoscope according to claim 1, wherein when theresults of comparison sent from the comparison unit demonstrate that thedriving state of the bending drive unit has reached the limit, thecontrol unit disconnects transmission of power exerted by the bendingdrive unit.
 4. The electric bending endoscope according to claim 1,wherein: the bending drive unit comprises bending operation wires thatbend the bending section, a bending motor that draws or releases thebending operation wires, and a sprocket that converts the driving forceexerted by the bending motor into the advancing or withdrawing motionsof the bending operation wires; and the state detection unit detects thedriving state of the bending motor.
 5. The electric bending endoscopeaccording to claim 4, wherein the state detection unit is a temperaturedetection unit that detects the temperature of the bending motor.
 6. Theelectric bending endoscope according to claim 4, wherein the statedetection unit is a driving signal detection unit that detects a drivingsignal with which the bending motor is driven.
 7. The electric bendingendoscope according to claim 4, wherein the state detection unit is atorque detection unit that detects the torque exerted by the bendingmotor.
 8. The electric bending endoscope according to claim 4, whereinthe state detection unit is a rotating speed detection unit that detectsthe rotating speed of the bending motor.
 9. The electric bendingendoscope according to claim 4, wherein the state detection unit is atension detection unit that detects the tensions of the bendingoperation wires.
 10. The electric bending endoscope according to claim4, wherein the state detection unit is a bent position detection unitthat detects the positions to which the bending operation wires arebent.
 11. The electric bending endoscope according to claim 4, whereinthe state detection unit is a rotational position detection unit thatdetects the rotational position of the sprocket.
 12. The electricbending endoscope according to claim 4, wherein the state detection unitis a rotating speed detection unit that detects the rotating speed ofthe sprocket.
 13. The electric bending endoscope according to claim 4,wherein the state detection unit is a mechanical use time detection unitthat detects the mechanical use time of the bending motor.
 14. Theelectric bending endoscope comprising: an elongated insertion unit; abending section formed adjacently to a distal section of the insertionunit; a bending drive unit for driving the bending section to bend; abending operation input unit for use in instructing bending of thebending section; a state detection unit for detecting the driving stateof the bending drive unit; a record unit in which the limits ofabilities of the bending drive unit are recorded; a comparison unit forcomparing the driving state detected by the state detection unit withthe limits recorded in the record unit; and a control unit for when theresults of comparison sent from the comparison unit demonstrate that thedriving state of the bending drive unit has reached the limit, stoppingsupply of energy to the bending drive unit.
 15. The electric bendingendoscope according to claim 14, wherein when the results of comparisonsent from the comparison unit demonstrate that the driving state of thebending drive unit has reached the limit, the control units notifies auser of the driving state of the bending drive unit.
 16. The electricbending endoscope according to claim 14, wherein when the results ofcomparison sent from the comparison unit demonstrate that the drivingstate of the bending drive unit has reached the limit, the control unitsdisconnects transmission of power exerted by the bending drive unit. 17.The electric bending endoscope according to claim 14, wherein: thebending drive unit comprises bending operation wires that bend thebending unit, a bending motor that draws or releases the bendingoperation wires, and a sprocket that converts the driving force exertedby the bending motor into the advancing or withdrawing motions of thebending operation wires; and the state detection unit detects thedriving state of the bending motor.
 18. The electric bending endoscopecomprising: an elongated insertion unit; a bending section formedadjacently to a distal section of the insertion unit; a bending driveunit for driving the bending section to bend; a bending operation inputunit for use in instructing bending of the bending section; a statedetection unit for detecting the driving state of the bending driveunit; a record unit in which the limits of abilities of the bendingdrive unit are recorded; a comparison unit for comparing the drivingstate detected by the state detection unit with the limits recorded inthe record unit; and a control unit that when the results of comparisonsent from the comparison unit demonstrate that the driving state of thebending drive unit has reached the limit, disconnects transmission ofpower exerted by the bending drive unit.
 19. The electric bendingendoscope according to claim 18, wherein when the results of comparisonsent from the comparison unit demonstrate that the driving state of thebending drive unit has reached the limit, the control unit notifies auser of the driving state of the bending drive unit.
 20. The electricbending endoscope according to claim 18, wherein when the results ofcomparison sent from the comparison unit demonstrate that the drivingstate of the bending drive unit has reached the limit, the control unitstops supply of energy to the bending drive unit.
 21. The electricbending endoscope according to claim 18, wherein: the bending drive unitcomprises bending operation wires that bend the bending unit, a bendingmotor that draws or releases the bending operation wires, and a sprocketthat converts the driving force exerted by the bending motor into theadvancing or withdrawing motions of the bending operation wires; and thestate detection unit detects the driving state of the bending motor.